Gas burner for coke ovens



y 1950 J. VAN ACKEREN GAS BURNER FOR COKE OVENS 2 Sheets-She et l FiledAug. 14, 1945 INVENTOR Josgpw vmv flcKgRE/V.

ATTORNEY May 16, 1950 J. VAN ACYKEREN GAS BURNER FOR com: OVENS 2Sheets-Sheet 2 Filed 14, 1945 INVENTOR Jose PH vmv 14ers RE/V.

ATTORNEY Patented May 16, 1950 GAS BURNER FOR COKE OVENS Joseph vanAckeren, Aspinwall, Pa., assignor to Koppers Company, Inc., Pittsburgh,Pa., a corporation of Delaware Application August 14, 1945, Serial No.610,692

3 Claims. I

This invention relates to gas burners. More particularly the inventionrelates to gas burners which are mounted in the refractory structure ofa coke oven battery to heat the coke ovens.

Two types of gas are commonly employed for heating coke ovens. One gasis a coke oven gas which has a heating value of 550 to 600 B. t. u.s percubic foot, while the other gas is a blast furnace gas which has aheating value of '75 to 90 B. t. u.s per cubic foot. The coke oven gaswill burn with a short, hot flame with preheated air while the blastfurnace gas burns with a long comparatively low temperature flame.

It is customary to dilute coke oven gas with waste flue gas to provide amixture having a heating value of from 250 to 300 B. t. u.s per cubicfoot. This mixture will burn with a long comparatively high temperatureflame, and provides an effective medium by which the oven can beuniformly heated throughout.

With a blast furnace gas having a heating value of-from 90 to 100 B. t.u.s per cubic foot an effective uniform heating of the oven may becarried out by preheating both the air and gas prior to combustion.Blast furnace gas having a heating value below 90 B. t. u.s per cubicfoot is generally not satisfactory for heating coke ovens and thereforecoke oven gas is generally mixed with the blast furnace gas to form amixture for heating the coke ovens. Attempts have been made to mix cokeoven gas directly with the blast furnace gas before sending the mixturethrough a regenerator to be preheated before combustion, but' suchpractice has not been found practicable because the coke gas is crackedin the regenerators and deposits carbon in the checker brick of theregenerator.- This carbon is burned on the reverse cycle of theregenerator and passes out to the waste gas flue. Thus the higher B. t.u. value of the coke oven gas is lost. It has been found satisfactory tomix coke oven gas with a blast furnace gas-air mixture at the mouth ofthe burner in the bottom of the combustion flues at the sides of theoven.

The mixing tube and burner nozzle for burning coke oven or rich gaspasses through a heated wall adjacent a regenerator to conduct the gasto the combustion fiues. The mixing tube is maintained at such a hightemperature that if straight coke oven gas is passed through the tube ata low Velocity the gas will crack and clog the tube with carbon. Toovercome this cracking, waste flue gas is mixed with the rich gas tospeed up the gas velocity and to provide a diluted mixture which willnot crack.

- erwise the burner mixer will not properly function to proportion therich gas with the waste gas.

The Venturi throat and mixtng tube of the gas burner are formed inrefractory shapes, which make up the regenerator walls. The regeneratorwalls undergo a comparatively large expansion when the oven andregenerators are being heated from a cold condition to the operatingtemperature. The burner refractory shapes accordingly move with theexpanding regenerator walls. It is important therefore that theconstruction and arrangement of the inspirating nozzle and Venturithroat of the burner shall maintain their fixed desired position withrelation to one another regardless of the expansion and contraction ofthe refractory walls and the movement of refractory burner shapes alongwith the regenerator walls.

The primary object of the present invention is to provide an aspiratingburner for coke ovens in which the measuring parts of the burner will bemaintained in their proper relative position when the oven structuremoves due to expansion and contraction under varying conditions of heat.

A further object of the invention is to provide an aspirating burnerbuilt into and forming parts of the oven structure that is subject toexpansion and contraction by which the parts of the aspirating burnerwill maintain their same relative gas measuring position as the ovenparts expand and contract.

With these and other objects in view the invention consists in theimproved gas burner hereinafter described and particularly defined inthe appended claims.

The various features of the invention are illustrated in theaccompanying drawing in which:

Figure 1 is a vertical sectional view of a part of an underjet coke ovenbattery illustrating the mounting in the furnace structure of a gasburner embodying the preferred form of the invention;

Figure 2 is a vertical sectional view of the furnace and burners ofFigure 1 taken at right angles to the section of Figure 1; and

Figure 3 is an enlarged detail view in vertical section showing themounting of the burners for heating flues at the opposite sides of acoke oven.

Referring to the drawings, in Figure 1, are illustrated coke ovens 18 onopposite sides of which are mounted heating flues l2 and I4. The heatingflues and coke ovens are separated by refractory walls and below thecoke ovens and flues are regenerators i6, i8, 28 and 22. Theregenerators are fllled with checker brick and the walls of theregenerators are of refractory materials, preferably a high temperaturesilica refractory.

The heating of the coke ovens is a continuous process which is carriedout in two parts. In the flrst half of the heating cycle air and fuelgas are introduced into the bottom of a heating flue, for example. l2.The products of combustion then pass up through the flue 12, thenthrough a cross-over flue 24 and down through a flue [4 across theopposite wall of oven l8. During this half of the heating cycle the flueI2 is termed the "on flue, and the flue I4 is termed the off flue.During the second half of the heating cycle gas in introduced into thebottom of the former off flue H. The products of combustion passupwardly through the flue l4 then through the cross-over flue 24 anddown through the former on flue l2. In the second half of the cycle theflue [4 becomes the on flue and the flue l2 the off flue. Therefore theon flue is that flue in which the gas is being burned and the off flueis the flue through which products of combustion from an on flue arepassedfor heating an oven wall. The products of combustion or wastegases, pass from the bottom of the off flues through the correspondingregenerator to heat the regenerator so that air which is introduced forburning the gas may be preheated by passing through the regenerator. Theregenerators therefore may be oil. and on in the cycle depending onwhether they are being heated by exhaust waste gases or whether they areused in preheating air for combustion.

The gas burners for heating the flues are mounted in the refractorysetting below the coke oven flues as illustrated in Figures 1 and 2. Thegas burners are made up of mixing tubes 26 which extend from the bottomof the flues down to the bottom of the regenerators. At the bottom ofthe mixing tube is a Venturi throat 28 which forms part of an aspiratingmixer. Immediately below the Venturi throat 28 is an inspirating nozzle30 which is arranged to direct gas supplied by a supply pipe 32 directlyinto the central portion of the Venturi throat 28. At the side of theVenturi throat is a waste gas inlet tube 34 by which waste gases aredrawn into'the mixing tube 28, by the action of the inspirating nozzlein the Venturi throat. The area beneath the Venturi throat 28 andsurrounding the nozzle 30 is in effect an inlet chamber to which theinlet passage 34 connects. The parts 26, 28, 30 and 34 constitute thegas burner and mixer apparatus.

When a flue is operating in oil condition, waste gases pass from thebottom of the flue, for example, flue [4 down through a mixing tube 26through a waste gas tube 34, then to a connecting tube 38 to the wastegas tube 34 of a gas burner supplying gas to the flue l2. The off and onburners are arranged in pairs along the longitudinal axis of an oven asshown in Figures 1 and 2. One burner operates as an on burner while theother burner is an off burner, the products of combustion passing intoand through the corresponding on and off flue. The burners supply richgas to the heating flues and it is customary to mix waste gas with therich gas in the mixer tubes 26 to adjust B. t. u. value of the gas toproduce a long flame combustion in the flues for effectively heating theflues. The rich gas ordinarily has a heating value of 550 to 600 B. t.u.s per cubic foot and sufllcient waste gas is mixed with the rich gasto produce a mixture of about 250 to 300 B. t. u.s per cubic foot. Sucha. mixture will not crack in the heated mixing tube 26 that is a part ofthe heated refractory wall of the regenerator.

When coke oven or rich gas is used solely for heating the flues l2 or H,preheated air is introduced into the bottom of the heating flue adjacentthe top of the mixing tube 26. If flue I2 is the on flue, then air forcombustion passes up through the regenerators l6 and IE to preheat theair. If I 4 is the on flue, then preheated air will pass upwardlythrough the regenerator 28 and the left half of the regenerator 22 tointroduce the gas-waste gas mixture at the top of the mixer tube 26.

If blast furnace gas is being used for heating the flues the blastfurnace gas is preheated by passing through a regenerator. Asillustrated in Figure 1, blast furnace gas will pass up through theregenerator 22 to be preheated and will flow therefrom through the lefthand passage at the top of the regenerator to the flue I4 where theblast furnace gas will meet with rich gas which is introduced into thebottom of the flue I 4 through a burner tube 26. The air for burning theblast furnace gas is introduced through the regenerator 20. During thispart of the cycle the regenerator l6 and regenerator l8 are heated bygases passingdownwardly through the flue I2. On the otherhalf of thecycle blast furnace gas is preheated in regenerator l6, burned in fluel2, then passes across and down through flue I4 and out throughregenerators 20 and 22. At the same time a rich gas-waste gas mixturepasses up through the burner tube 26 to assist in burning the blastfurnace gas.

The construction and arrangement of the burners in the oven structureconstitutes an important feature of the present invention. The burnerparts, such as the mixer tube 28, the Venturi throat 28, the inletchamber beneath the Venturi throat, and the gas inlet passage 34 areformed in and constitute parts of refractory shapes that are used inbuilding up the regenerator walls of the furnace structure. Theserefractory shapes which make up the burner parts arev held together witha cement which will cause all of the burner parts to move as a unitunder the expansion and contraction movement of the regenerator wallstructure. The refractory structure is mounted upon a fixed concrete mat38. The regenerator walls and burner shapes are movably mounted on themat 38 to permit movement of the shapes under various conditions ofexpansion and contraction. As shown in Figure 3, the refractory shapessurrounding the connecting tube 36 are provided with expansion joints 40to permit expansion of the shapes longitudinally of the tubes 36 ortransversely of the coke oven. Other expansion joints are provided topermit movement of the burner shapes and regenerator wallslongitudinally of the coke oven. By having the burner parts formed aspart of the refractory shapes the expansion and contraction of theshapes will not deform the burner parts 26, 28 or 34. To cause theinspirating nozzle 30 to direct gas into the central portion of theVenturi throat 28 the nozzle is rigidly secured to a metal block oranchor member 42 which is mounted with cement 43 in the refractory shape44 that forms the base of the aspirating mixer. Therefore when the shape44 moves transversely or longitudinally of the oven the nozzle 30 willmove with the shape and maintain its accurately centered position belowthe Venturi throat. The metal block 42 is not attached to the uppersurface of the mat 38 but may move along the surface of the mat underexpansion and contraction of the refractory material surrounding andenclosing the block. The nozzle 30 is secured to the metal block 42 byscrew-threads and may be inserted and removed through the supply pipe32. By this means different sizes of nozzles may be inserted into theburner to obtain any desired supply of gas to the burner. It will beunderstood that the nozzle used for supplying rich gas when the ovensare being heated with oven gas will be larger and of a different typethan the nozzle which is used when the burners are supplying a smallamount of gas for enriching blast furnace gas. Supply pipe 32 will movewith the metal block or anchor member 42 under expansion and contractionof the refractory shape 44 and therefore an enlarged opening 46 isprovided in the mat 38 to permit the pipe to move with the metal block42. The lower end of the supply pipe 32 is connected by means of aflexible tubing 48 with a gas supply main 50, this flexible tubingpermitting the movement of the pipe 32 under expansion and contractionof the refractory burner parts.

The principal expansion of the oven structure and walls takes place whenthe oven is heated from a cold condition to a hot operating condition.Some expansion or contraction also takes place when the operatingtemperature is materially changed for coking different types of coal.The main expansion and contraction of the refractory structure takesplace longitudinally of the coke oven from the center outwardly to bothends of the oven. There is also expansion and contraction movement ofthe oven structure transversely of the coke oven, this expansion beingfrom the center of an oven battery in opposite directions to both endsof the battery.

The connecting tube 36 for conducting the waste gases that arerecirculated through the burners is loosely mounted in the refractoryshapes to provide for the expansion and contraction of the furnacestructure. The tube 36 is made up of a metallic tubular outer shell 52with a refractory lining 54, the refractory preferably being a clayrefractory. The refractory shapes which surround the tube 36 makes aclose, but

sliding, lit with the tube, whereby the refractory shapes may moveindependently of the tube and thus permit the tube to expand andcontract independently of the expansion and contraction of the shapessurrounding it. Asbestos gaskets 56 at each end of the tube 36 are usedfor packing in the expansion joints to close the gap between the outsideof the tube and the circular opening in the shapes so that the wastegases will be caused to flow to the center through the opening in thetube.

As illustrated in Figure 2 the gas burners are formed in pairs atopposite sides of an oven. The waste gas tubes 34 of each pair ofburners are connected together and one cross connecting tube 36 isarranged between the burners to supply waste gases simultaneously toeach of the pair of burners.

The preferred form of the invention having been thus described, what isclaimed as new is:

1. In a structure of the class described, in combination, a supportingmat, refractory shapes mounted on and supported by said mat to form aplurality of regenerators with parallel dividing walls and above whichare located coking chambers which are parallel with the regeneratordivision walls, each of said coking chambers being intermediate a pairof vertically flued heating walls with the flues in said wallscommunicably interconnected at their upper parts into a first and asecond set for operation in alternation, said refractory shapes havinginlet chambers formed therein above said supporting mat, each of saidinlet chambers being connected to the lower part of a vertical flue by aburner tube formed in said refractory shapes and having a Venturi throatadjacent its lower end, each inlet chamber being connected through aconnecting conduit formed in said refractory shapes with the inletchamber associated with a flue in a different set, each of said inletchambers having located thereunder a metal plate supported on saidsupporting mat and incorporated in said refractor shapes so as to bemovable therewith, each of said plates having a fuel gas supply pipesecured thereto and extending downwardly through an opening in saidsupporting mat, each of the openings in said supporting mat beingsubstantially larger in size than the associated supply pipe to therebypermit unrestrained move ment of said pipe relative to said mat, and anozzle associated with each inlet chamber and disposed to direct fuelgas supplied through the associated supply pipe directly into thecentral part of the Venturi throat of the associated burner tube, eachof said nozzles being supported from and movable with the metal platelocated beneath the associated inlet chamber, whereby on expansion andmovement of said refractory shapes each of said nozzles is maintained insubstantially the correct relationship to the Venturi throat of theassociated burner tube.

2. In a structure of the class described, in combination, a supportingmat, refractoryv shapes mounted on and supported by said mat to form aplurality of regenerators with parallel dividing walls and above whichare located coking chambers which are parallel with the regeneratordivision walls, each of said coking chambers being intermediate a pairof vertically flued heating walls with the flues in said wallscommunicably interconnected at their upper parts into -a first and asecond set for operation in alternation, said refractory shapes havinginlet chambers formed therein above said supporting mat, each of saidinlet chambers being connected to the lower part of a vertical flue by aburner tube formed in said refractory shapes and having a Venturi throatadjacent its lower end, each inlet chamber being connectedthrough a.connecting conduit formed in said refractory shapes with the inletchamber associated with a flue in a different set, a metallic anchormember located beneath each of said inlet chambers, each of said anchormembers having a fuel gas supply pipe secured thereto and extendingdownwardly through an opening in said supporting mat of substantiallylarger size than said pipe, each of said anchor members having rigidlyand detachably secured thereto an upwardly extending gas nozzle disposedsubstantially co-axially of the Venturi throat of the associated burnertube and adapted to direct into the central part of said Venturi throatfuel gas supplied through the associated supply pipe,each of said anchormembers being rigidly incorporated in said refractory shapes so as to bemovable with said refractory shapes on expansion thereof, whereby onexpansion and movement of said refractory shapes each of said nozzles ismaintained in substantially the correct relationship to the Venturithroat of the associated burner tube.

3. In a horizontal coke oven of the underjet t pe, in combination, asupporting mat, refractory shapes mounted on and supported by said matto form a first and a second substantially vertical wall which arespaced apart a short distance, said refractory shapes having formedtherein a first inlet chamber beneath said first wall and a second inletchamber beneath said second wall, each of said walls having a burnertube formed therein and leading upwardly from the associated inletchamber, each of said burner tubes having a Venturi throat adjacent itslower end, said refractory shapes having a passage formed therein andconnecting said first and second inlet chambers, a metal tube ofsomewhat smaller diameter than said passage loosely mounted in saidpassage, a yieldable packing element adjacent each end of said tube andpositioned between said tube and said passageway to permit movement ofthe tube in said passageway, a fuel gas supply pipe chamber and disposedsubstantially co-axially of the Venturi throat of the associated burnertube to direct fuel gas supplied through the associated supply pipedirectly into the central part of the Venturi throat of the associatedburner tube, each of said nozzles and the associated supply pipe beingrigidly mounted with respect to said refractory shapes and being movablewith respect to said supporting mat, whereby on expansion and movementof said refractory shapes each of said nozzles is maintainedsubstantially co-axially of the Venturi throat of the associated burnertube.

JOSEPH vm ACKEREN.

REFERENCES CITED The following references are of record in the tile ofthis patent:

UNITED STATES PATENTS Great Britain Oct. 29, 1937

